ULTRASONOGRAPHIC ANATOMY OF THE NORMAL CANINE STIFLE

Ultrasonographic examination of the normal canine stifle joint was performed to characterize its normal anatomy. Stifles of four normal adult dogs were imaged in sagittal and transverse planes and each anatomic structure visualized was recorded. Normal anatomic structures consistently seen included the patellar tendon, medial and lateral menisci, the cranial cruciate ligament and femoral condyle cartilage. The caudal cruciate ligament was visualized in two dogs. Collateral ligaments and meniscal ligaments were not visualized. The dogs were then euthanized and each stifle was isolated. Following removal of superficial muscles and skin, each stifle was imaged in a water bath to definitively identify the structures that had previously been visualized on the live dogs. The ultrasonographic appearance of the isolated stifle specimens was similar to that found in live dogs. The results of this study indicate that ultrasound can be used to image the normal anatomy of the canine stifle. The echogenicity of the patellar ligament, cruciate ligaments, menisci and articular cartilage was similar to that previously reported in equine stifles and human knees.     

COMPUTED TOMOGRAPHIC ARTHROGRAPHY OF THE NORMAL CANINE STIFLE

Computed tomographic (CT) imaging of eight normal cadaveric canine stifles was performed before and after intra-articular administration of iodinated contrast medium. Transverse CT images were reconstructed in dorsal, parasagittal, and oblique planes. The following ligamentous structures were identified on transverse CT images in all stifles: cranial cruciate ligament, caudal cruciate ligament, medial meniscus, lateral meniscus, and the medial and lateral collateral ligaments. The following ligamentous structures were identified on transverse computed tomographic arthrography (CTA) images in all stifles: cranial cruciate ligament, caudal cruciate ligament, medial meniscus, lateral meniscus, meniscofemoral ligament, cranial meniscotibial ligaments, caudal meniscotibial ligaments, intermeniscal (transverse) ligament, and the medial and lateral collateral ligaments. The patellar tendon was identified on transverse and reconstructed dorsal and sagittal CT and CTA images in all stifles. Multiplanar reconstructions enabled further evaluation of the continuity of the cranial and caudal cruciate ligaments and menisci. The medial and lateral collateral ligaments were not clearly identified on CT or CTA multiplanar reconstructed images.     

Evaluation of the Marsh Deer Stifle Joint by Imaging Studies and Gross Anatomy

This study aimed to evaluate the stifle joint of marsh deer using imaging studies and in comparison with gross anatomy. Ten hindlimbs from 5 marsh deer (Blastocerus dichotomus) were used. Radiography, computed tomography (CT) and magnetic resonance imaging (MRI) were performed in each stifle joint. Two hindlimbs were dissected to describe stifle gross anatomy. The other limbs were sectioned in sagittal, dorsal or transverse planes. In the craniocaudal radiographic view, the lateral femoral condyle was broader than the medial femoral condyle. The femoral trochlea was asymmetrical. Subsequent multiplanar reconstruction revealed in the cranial view that the external surface of the patella was roughened, the medial trochlea ridge was larger than the lateral one, and the extensor fossa at the lateral condyle was next to the lateral ridge. The popliteal fossa was better visualized via the lateral view. Sagittal MRI images identified lateral and medial menisci, caudolateral and craniomedial bundles of cranial cruciate ligament, caudal cruciate ligament, patellar ligament and common extensor tendon. In conclusion, the marsh deer stifle presents some anatomical characteristics of the ovine stifle joint.     

MAGNETIC RESONANCE IMAGING OF THE EQUINE STIFLE

The purpose of this study was to define normal gross anatomic structures in the equine stifle with magnetic resonance images. Magnetic resonance (MR) images were made in sagittal, 15° supinated, transverse, and dorsal planes of two equine stifles. The MR images were scrutinized by comparing MR images to dissection specimens and frozen cross sections of stifle joints. Sagittal and 15° supinated images were the most valuable in assessing articular cartilage, subchondral bone, and soft tissue structures within the joint. Cranial and caudal cruciate ligaments, medial and lateral menisci, meniscotibial and meniscofemoral ligaments, long digital extensor tendon, and patellar ligaments were easily evaluated. MR images provided substantially more gross anatomical information than the currently available imaging modalities.     

Determination of the normal arthroscopic anatomy of the femoropatellar and cranial femorotibial joints of cattle

The arthroscopic approach and anatomy of the bovine femoropatellar and femorotibial joints are described. A 4-mm diameter, 15-cm long arthroscope with a 30° forward angle view was used. The structures viewed were recorded according to the position of the arthroscope within the joint. The femoropatellar joint was best accessed via a lateral approach, between the middle and lateral patellar ligaments. The axial portion of the medial femorotibial joint was viewed from a medial approach between the middle and medial patellar ligaments and the abaxial portion was viewed from a lateral approach between the middle and the lateral patellar ligaments. The axial portion of the lateral femorotibial joint was viewed from a lateral approach between the middle and the lateral patellar ligaments and the abaxial portion was viewed from a medial approach between the middle and medial patellar ligaments. The results of this study provide guidelines regarding the location of arthroscopic portals to evaluate precisely different areas of the stifle in cattle.     

Caudal cruciate ligament function and injury in the horse

The caudal cruciate ligament assists the medial femorotibial ligament in supporting the medial aspect of the femorotibial joint. It also limits the outward rotation of the tibia during weight bearing. In two lame horses tearing of the caudal portion of the femoral attachment of the caudal cruciate ligament was recorded together with cracking and tearing of the medial meniscus. In one case, synovitis and restrictive fibrous periarthritis were the sequelae of secondary stifle sepsis.     

Canine stifle positive contrast computed tomography arthrography for assessment of caudal horn meniscal injury: a cadaver study

Objective— To investigate the use of computed tomography (CT) arthrography in cadaveric canine stifles with particular emphasis on the diagnosis of meniscal injury.
Study Design— Prospective cadaver study.
Sample Population— Pelvic limbs from adult Beagles (n=10).
Methods— After survey CT scan of each stifle oriented in the dorsal plane, positive contrast stifle CT arthrogram (CTA) was performed using the same slice orientation. Each stifle was then randomly allocated into 1 of 2 treatment groups: group A—arthrotomy, cranial cruciate ligament (CCL) transection and simulated injury to the caudal horn of the medial meniscus; group B—arthrotomy and CCL transection only. CT scan was repeated as before and post-arthrotomy images were interpreted by a radiologist unaware of treatment grouping.
Results— The cranial and caudal cruciate ligaments, medial and lateral menisci, menisco-femoral ligament, and long digital extensor tendon were all identifiable on CTA images. CTA was 90% sensitive and 100% specific for diagnosing simulated caudal horn meniscal injury.
Conclusions— Stifle CTA enables identification of intra-articular structures within the stifle and is a reliable method for identifying simulated meniscal injuries in a cadaver model.
Clinical Relevance— CTA imaging of the canine stifle has potential clinical value for detection of meniscal injury.     

Factors affecting width of the canine femorotibial joint space in nonweight-bearing radiographs.

Caudocranial stifle radiographs with variations in positioning were made in two greyhound cadavers. Radiographs were repeated after each of three interventions: cranial cruciate desmotomy; release of the caudal horn of the medial meniscus; complete medial meniscectomy. The joint space on medial and lateral aspects of the joint was measured by a observer who was unaware of positioning or intervention. One dog had significantly wider joint space than the other (1.0 vs. 1.5mm). The lateral aspect of the joint space was wider than the medial aspect (1.7 vs. 0.7 mm). Medial rotation of the stifle resulted in an increase of 0.4 mm in width of the lateral joint space, whereas lateral rotation of the stifle reduced the lateral joint space by an average of 0.4 mm. Decentering the X-ray beam had no significant effect on joint space width. Tension increased the width of the medial joint space by an average of 1.2 mm and the lateral aspect by an average of 1.3 mm. Cranial cruciate desmotomy resulted in an average 0.3 mm increase in width of the joint space, and medial meniscectomy with an average 0.2 mm reduction of the joint space. Although the femorotibial joint space was affected by iatrogenic stifle injuries and by medial or lateral rotation, these changes were less than the differences between the two dogs. Hence it seems unlikely that the small changes in joint space width associated with cruciate ligament desmotomy and medial meniscectomy will be detectable in clinical practice.     

Correlation between osteoarthritic changes in the stifle joint in dogs and the results of orthopedic,radiographic, ultrasonographic and arthroscopic examinations

Osteoarthritis (OA) is a chronic, degenerative disease affecting the articular cartilage and subchondral bone that causes pain and inhibits movement. The stifle’s joint fibrous capsule contains the synovial membrane, which produces cartilage nutrients. A ruptured cranial cruciate ligament injures the joint and produces OA. Osteoarthritis diagnosis starts with clinical radiographic and ultrasonographic tests, although the latter is not used very much in dog and cat clinics for this purpose. The objective of this study was to establish the correlation among the results of orthopedic, radiographic, ultrasonographic examinations and structural anatomical changes revealed by arthroscopic evaluation to diagnose stifle joint OA and determine risk factors in the dogs affected. Of 44 clinical cases of OA included in the study, 88.64% had ruptured of cranial cruciate ligaments. The correlation between synovial fluid effusion and osteophytosis was of 0.84. It was concluded that there is good diagnostic agreement between synovial fluid effusion and osteophytosis when dealing with stifle joint OA. Risk factors for dogs regarding the development of stifle joint OA included: ruptured cranial cruciate ligaments or patella luxation, female dogs and weight over 10 kg.     

Stifle joint luxation in the dog and cat: the use of temporary intraoperative transarticular pinning to facilitate joint reconstruction.

Multiple ligament injuries of the canine and feline stifle joint which result in luxation are uncommon. Two cats and one dog, that had sustained such a joint injury were surgically treated. A rupture of the cranial and caudal cruciate ligaments, and at least one collateral ligament was observed in all of the three animals. Prosthetic reconstruction was used, as previously described, in combination with a novel technique of intraoperative placement of a temporary trans-articular pin (TTP) to maintain intra-operative anatomical reduction. TTP placement facilitated maintenance of joint alignment during surgical reconstruction and aided appropriate tensioning of the prosthetic sutures, preventing collapse of femorotibial joint compartments. The TTP was removed prior to closure of the joint allowing immediate post-operative joint mobilisation. Based on assessment by their owners, all the animals made a complete recovery. TTP was considered a relatively simple and effective adjunctive aid for surgical treatment of traumatic luxation of the stifle joint.     

Multiple ligamentous injuries of the canine stifle joint: a study of 12 cases

Multiple ligamentous injuries of the canine stifle are uncommon. In this study, they affected mainly adult, male, working or sporting dogs and occurred secondary to severe trauma, or where chronic joint infection had weakened the supporting structures. Rupture of the cranial cruciate, caudal cruciate and lateral collateral ligaments was the most common injury observed and this occurred after catching the limb in a fence or gate. Reconstruction of the collateral and cranial cruciate ligaments, and careful repair of damaged menisci and joint capsule, was an effective method of treatment for medium- and large-size dogs. Reconstruction of the caudal cruciate ligament and postoperative limb support was not found to be essential. All dogs with subluxated stifles had good to excellent limb function with minimal loss of mid-thigh circumference or stifle joint range of motion at follow-up. Less favourable results were achieved where there was stifle joint luxation with extensive disruption to secondary joint restraints.     

Correlative biomechanical and histologic study of the cranial cruciate ligament in dogs

The mechanical properties of the cranial cruciate ligament were determined, using unilateral bone-ligament-bone preparations from 65 dogs of various ages and body sizes. Tensile loading of the cranial cruciate ligament from 1 of each pair of stifle joints demonstrated a decrease in material properties (modulus, maximum stress, strain energy) with aging. The decreases in maximum stress and strain energy with age were significantly less (P less than 0.05 and P less than 0.05, respectively) in the cranial cruciate ligament from dogs weighing less than 15 kg, compared with those weighing 15 kg or more. The cranial cruciate ligament and remaining femorotibial ligaments were collected from the opposite stifle joints and examined microscopically. By 5 years of age, the cranial cruciate ligaments of dogs weighing greater than 15 kg consistently had microscopic evidence of degenerative disease (loss of ligamentocytes, metaplasia of surviving ligamentocytes to chondrocytes, and failure to maintain collagen fibers and primary collagen bundles) which progressed in severity with age. The caudal cruciate ligaments were similarly affected, although the degenerative changes were rarely as severe as in the cranial cruciate ligament. The collateral ligaments underwent minimal degeneration. Sex differences had no bearing on degeneration. The cranial cruciate ligaments in dogs weighing less than 15 kg generally had less severe alterations than those in heavier dogs, and the onset of the degenerative process was delayed by several years. Cranial cruciate ligaments removed from dogs after ligament failure not only had degenerative disease, but also had undergone unsuccessful attempts at repair. In contrast, fibrous repair was rarely present in intact ligaments of asymptomatic dogs with degenerative disease of the cranial cruciate ligament.     

Cranial cruciate ligament injury in the dog: pathophysiology, diagnosis and treatment

Cranial cruciate ligament (CCL) disease in the dog is a multifactorial complex problem that requires a thorough understanding of the biomechanics of the stifle joint to be understood. Successful treatment of rupture of the CCL should be based on managing underlying anatomical and conformational abnormalities rather than attempting to eliminate the tibial cranial drawer sign. The cranial and caudal cruciate ligaments, the patella ligament and quadriceps mechanism, the medial and lateral collateral ligaments, the medial and lateral menisci and the joint capsule provide stability of the joint and load-sharing. The function of the stifle is also significantly influenced by the musculature of the pelvic limb. An active model of biomechanics of the stifle has been described that incorporates not only the ligamentous structures of the stifle but also the forces created by weight-bearing and the musculature of the pelvic limb. This model recognises a force called cranial tibial thrust, which occurs during weight-bearing, and causes compression of the femoral condyles against the tibial plateau. In middle-aged, large-breed dogs, forces acting on the CCL together with conformation-related mild hyperextension of the stifle and slightly increased tibial plateau slopes are suspected to cause progressive degeneration of the ligament. Palpation of craniolateral stifle laxity has become pathognomonic for CCL rupture; however, chronic periarticular fibrosis, a partial CCL rupture, and a tense patient, may make evaluation of instability of the stifle difficult. Surgical treatment is broadly separated into three groups: intracapsular, extracapsular, and tibial osteotomy techniques. Tibial osteotomy techniques do not serve to provide stability of the stifle but rather alter the geometry of the joint to eliminate cranial tibial thrust such that functional joint stability is achieved during weight-bearing. Visualisation of both menisci is a critical aspect of CCL surgery, irrespective of the technique being performed. Regardless of the surgical technique employed, approximately 85% of dogs show clinical improvement. However, many of these dogs will demonstrate intermittent pain or lameness. Post-operative management is an integral part of the treatment of CCL rupture, and significant benefits in limb function occur when formalised post-operative physiotherapy is performed.     

Intra-Articular Replacement of Bovine Cranial Cruciate Ligaments with an Autogenous Fascial Graft

Transected cranial cruciate ligaments in nine Holstein heifers were replaced with an autograft harvested from fascia on the medial surface of the gluteobiceps muscle and a connected segment of the lateral patellar ligament. There was minimal lameness at month 1, and all animals were sound by month 2. There was no evidence of degenerative joint disease in any stifles examined at necropsy on days 90, 120, or 365. Augmented healing of the severed cranial cruciate ligaments occurred in several animals. The mean failure strength of the cranial cruciate ligament replacements was 29.7% of the failure strength of the contralateral normal cranial cruciate ligament in four heifers. The technique was successful in eight of 13 bulls and cows with ruptured cranial cruciate ligaments. Animals treated successfully had significantly lower body weights than those with unsuccessful outcomes.     

Complex stifle injury in a foal

A 130 kg, 60-day-old Quarter Horse male foal presented with bilateral stifle effusion and severe left hindlimb lameness. Clinical examination and imaging including radiography, ultrasound and computed tomography revealed bilateral stifle trauma. Specifically, disruption of the left medial meniscus and deep bone injury to the left medial femoral condyle (MFC) were detected, and bilateral injury to the origin of the cranial cruciate ligaments was suspected. Treatment consisted of stall rest and joint injection with corticosteroids, however there was little improvement in lameness. Due to the poor prognosis for soundness, the foal was subject to euthanasia 10 weeks after initial presentation. Post-mortem examination supported the left medial meniscus and MFC injuries and revealed avulsions of the origin of the cranial cruciate ligaments (complete on the left and partial on the right) from the lateral femoral condyle. Histopathology of the left stifle joint revealed varying depths of MFC osteochondral injury and severe left medial meniscus damage.     

Arthroscopic Examination of the Femorotibial Joints of Horses

A technique for satisfactory arthroscopic examination of the lateral and medial femorotibial joints of the horse is described. The entry portal is made between the middle and medial patellar ligaments with the horse on its back and the stifle flexed. This position allows easy access to view the intercondylar eminence of the tibia. From this reference point, examination of all but the most caudal and medial structures of the joints are possible by manipulating the sleeve and telescope and maintaining joint distention. In a series of 20 examinations, iatrogenic trauma was recognized only once.     

Anatomic femorotibial changes associated with tibial plateau leveling osteotomy

This prospective study evaluated anatomic femorotibial changes utilizing the relationship between the intercondylar notch and the intercondylar eminence following tibial plateau leveling osteotomy (TPLO). We hypothesized that TPLO results in anatomic alteration of the femorotibial joint. Pre- and post-operative computed tomography (CT) scans of cranial cruciate deficient stifle joints treated with TPLO were performed on 25 client-owned dogs. Computed tomography scans were performed at 3 different stifle angles: extension, 135° walking angle, and 90° of flexion. Tibial plateau leveling osteotomy did not result in a significant medial or lateral shift of the intercondylar eminence relative to the intercondylar notch. There was a significant cranial shift of the intercondylar eminence with the stifle in extension following TPLO. In addition, TPLO resulted in a significantly narrowed femorotibial joint space. The biomechanical effects of TPLO and medial meniscal release need to be further defined.     

Radiographic measurement of craniocaudal instability in stifle joints of clinically normal dogs and dogs with injury of a cranial cruciate ligament

OBJECTIVE: To determine craniocaudal laxity of the stifle joint of dogs when joints were positioned in tibial compression or neutral position. SAMPLE POPULATION: 19 normal stifle joints in 10 clinically normal dogs, 29 stifle joints with varying injury to the cranial cruciate ligament (10 complete ruptures alone, 10 complete ruptures with concomitant damage to the medial meniscus, 6 partial ruptures alone, and 3 partial ruptures with concomitant meniscal tearing), and 19 unaffected contralateral stifle joints in those 29 dogs. PROCEDURE: Relative displacement of bony landmarks was measured on paired lateral radiographs (neutral and tibial compression positions). Two measuring techniques were customized for use in dogs. RESULTS: The first technique failed to distinguish results in normal stifle joints from those in stifle joints with partial deficiency of cranial cruciate ligaments. Significant differences were found for joints with complete rupture, compared with stifle joints in clinically normal dogs. The second technique detected differences between normal stifle joints and injured joints with partial or complete rupture of the cranial cruciate ligament. Significant differences were not detected between joints with partial versus complete rupture. Adjusting data to account for size of dog did not improve results. CONCLUSIONS AND CLINICAL RELEVANCE: A wide range in measurements of laxity was found for stifle joints with intact cranial cruciate ligaments. Differences in degree of damage to the ligament and medial meniscus cannot be deduced from the amount of relative displacement measured on radiographs. Pathologic changes to the cranial cruciate ligament will not necessarily induce detectable changes in laxity of stifle joints in dogs.     

Evaluation of a cranial arthroscopic approach to the stifle joint for the treatment of femorotibial joint disease in horses: 23 cases (1998-1999)

OBJECTIVE: To describe a single-portal cranial arthroscopic approach to the stifle joint in horses and to determine the clinical outcome in horses with femorotibial joint disease in which this approach was used. DESIGN: Retrospective study. ANIMALS: 23 adult horses. PROCEDURE: Medical records were reviewed to obtain information on clinical outcome in horses in which the single-portal cranial arthroscopic approach was used. RESULTS: Twenty-nine stifle joints of 23 horses were examined arthroscopically, using the described approach. Subchondral bone cysts were treated in 19 medial femoral condyles of 12 horses. Unilateral cruciate ligament desmitis (4 horses), meniscal tearing (3), or both (2) were identified in 9 horses. Evidence of degenerative joint disease without cystic lesions or soft tissue trauma was found in 2 horses. Information on clinical outcome was obtained for 21 of 23 horses. A successful outcome was obtained in 15 of 21 horses and was defined as return to sound performance at a degree equal to or better than that prior to injury and lameness. Eight of 12 horses treated for medial femoral condylar cysts had a successful outcome. Four show horses treated for cruciate ligament lesions alone successfully returned to showing activity. None of the 3 horses with meniscal tearing were able to perform successfully. CONCLUSIONS AND CLINICAL RELEVANCE: The femorotibial joint was evaluated through a single-portal cranial arthroscopic approach, using the femoropatellar joint as the point of access. This approach was easy to perform, allowed controlled access to the femorotibial joint, avoided accidental damage to articular structures, and required fewer access portals.